Even the best telescopes can’t see exoplanets. It’s all about watching for jiggly stars, blue shifts, and transits.

A Mars-size object called Theia smashed into Earth, and the debris coalesced into the moon. Now scientists believe they may have identified pieces of Theia at the bottom of Earth’s mantle. A new study ...

Mercury will sextile Pluto on Dec. 13, adding a layer of both intensity and enlightenment to our exchanges. Here's what the ...